Apparatus for monitoring the state of charge of a battery
First Claim
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1. An apparatus for monitoring the state of an electrical energy source comprising:
- a current sensor operatively connected to the energy source for producing an output signal related to the magnitude and direction of the current flowing to or from said energy source;
an electrical long term analog integrator connected to said current sensor for integrating said output signal and for producing a signal related to the state of the energy source;
said integrator including a long term charge storage device for storing a charge related to the state of the energy source;
said integrator charging at a rate proportional to the magnitude of the sensed current when the current flow is in one direction, and discharging at a rate proportional to the magnitude of the sensed current when the current flow is in the opposite direction;
said long term charge storage device being non-volatile in its charge retention when unconnected to a discharge circuit; and
conductors and an active circuit element responsive to the current sensed by the current sensor for automatically opening the circuit to the storage device when no current is flowing to or from the energy source.
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Abstract
An apparatus for monitoring the state of charge of a battery having a shunt resistor connected in series with a battery and an integrating circuit connected across the terminals of the shunt resistor. The integrating circuit includes a memoriode having a large capacitance and the capability to store charge for long periods of time, so that the integration can be performed along the same curve even if power to the integrating circuit is interrupted.
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Citations
34 Claims
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1. An apparatus for monitoring the state of an electrical energy source comprising:
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a current sensor operatively connected to the energy source for producing an output signal related to the magnitude and direction of the current flowing to or from said energy source; an electrical long term analog integrator connected to said current sensor for integrating said output signal and for producing a signal related to the state of the energy source; said integrator including a long term charge storage device for storing a charge related to the state of the energy source; said integrator charging at a rate proportional to the magnitude of the sensed current when the current flow is in one direction, and discharging at a rate proportional to the magnitude of the sensed current when the current flow is in the opposite direction; said long term charge storage device being non-volatile in its charge retention when unconnected to a discharge circuit; and conductors and an active circuit element responsive to the current sensed by the current sensor for automatically opening the circuit to the storage device when no current is flowing to or from the energy source. - View Dependent Claims (2, 3, 4)
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5. An apparatus for monitoring the state of an electrical energy source comprising:
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a current sensor operatively connected to the energy source for producing an output signal related to the magnitude and direction of the current flowing to or from said energy source; a capacitive element having a capacity of more than one farad connected to said current sensor for integrating said output signal and for producing a signal related to the state of the energy source; said capacitive element charging at a rate proportional to the magnitude of the sensed current when the current flow is in one direction, and discharging at a rate proportional to the magnitude of the sensed current when the current flow is in the opposite direction, on a continuous basis as the current flows to and from said energy source. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of monitoring the state of an electrical energy source comprising the steps of:
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sensing the direction and amount of current flow into and out of the energy source; integrating the net amount of said current flow continuously as current flows into and out of said energy source; the step of integrating comprising charging a capacitive element having an effective capacity of more than one farad in response to current flow in one direction, at a charge rate that is in proportion to the amount of current flow, and discharging the capacitive element in response to current flow in the opposite direction at a discharge rate that is in proportion to the amount of current flow. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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24. A method of monitoring the state of charge of a battery comprising the steps of:
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sensing the current flow to and from the battery; automatically charging and discharging a capacitive element in a long time constant circuit in response to, and in proportion to, the magnitude and direction of the sensed current flow, so that the charge across the capacitive element is continually proportional to the charge of the battery; compensating for any current flow from the battery that reaches a sufficiently high level by discharging the capacitive element at a predetermined rate during the period of time that the high current flow level continues. - View Dependent Claims (25, 26, 27, 28, 29)
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30. A method of monitoring the state of an electrical energy source comprising the steps of:
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initializing a capacitive element having an effective capacity of one farad or more by charging it corresponding to the state of the energy source; sensing the current flow to and from the energy source and automatically increasing and decreasing the charge on the capacitive element in proportion to the current flow to and from the energy source, for the entire periods of time that the current is flowing to and from the source; and automatically discharging the capacitive element at a predetermined discharge rate when the current flow out of the source reaches a predetermined value, for as long as the current flow remains at or above the predetermined value. - View Dependent Claims (31, 32, 33, 34)
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Specification